1. Field of the Invention
This invention relates generally to the mounting and dismounting of tires on a rim, and, more particularly, to an apparatus and method of mounting, and dismounting and cutting of tires from a wheel while the wheel remains attached to a vehicle.
2. Description of Related Art
Applicant""s U.S. Pat. No. 6,247,516, issued on Jun. 19, 2001 described one type of tire changer and mounting apparatus, that also cuts tires on a rim. The disclosure of this U.S. Pat. No. 6,247,516 (xe2x80x9c""516xe2x80x9d) is incorporated herein, in its entirety, by this reference thereto.
Although the device and method described in the ""516 patent mounts or dismounts and may cut a tire while the wheel remains on the vehicle, performs very well, the methods and apparatus of the present invention are considered to be an improvement thereto.
The ""516 patent utilizes a bead deflecting device juxtaposed to a stationary rim and a rotating tire to effectively deflect the moving bead of the tire over the flange of the rim. This method, repeated for both beads of a tire, either mounts or dismounts a tire from a wheel while the wheel remains affixed to the car. This method works well, but an alternative method has been discovered and is deemed even more advantageous. Because of the stability of the apparatus of the present invention, as described below, it has been found to be more beneficial to leave the wheel free to rotate on a vehicle""s axle and omit the use of a separate bead deflecting device. Instead, the beads of a tire are deflected over the flange of a rim with rotating dowels that are moved laterally across the width of the rim, as both the tire and its related wheel assembly are rotated on the vehicle. This technique eliminates the need to lock and unlock a vehicle""s axle between the three different operations of cutting, mount/dismounting and balancing, as is required in the ""516 patent. This improved method also eliminates the need to affix anything to the wheel, such as a bead deflector, thereby eliminating any possibility of damage to the wheel. The absence of these steps also speeds up operation time, thereby saving on labor.
The ""516 patent discloses a machine that is placed in position under a tire after a vehicle has been raised by a separate jack. It also described how the vehicle is lowered by the jack so the wheel and tire assembly rest upon the body of the machine in order to apply pressure between the tire and a pair of rotating drums held in the machine to eliminate slippage between the same. In order to eliminate the need for a jack and, therefore, reduce the size of the tire changing apparatus for ease of mobility, the present invention provides an apparatus that embodies a lifting mechanism which raises the tire and wheel assembly off the ground. The present invention also includes a jack stand mechanism placed so that the weight of the vehicle""s frame is lowered onto the jack stand. The jack stand, in turn, stabilizes the apparatus to prevent it from moving during operation. The same lifting mechanism used to raise the vehicle is also used to elevate separate motorized drums into the suspended tire and wheel assembly in order to make a non-slip contact between the motorized drums and the tire.
The ""516 patent also describes an apparatus that applies equal pressure of two rotating drums on a tire to be mounted or dismounted. Research has shown that this works well. However, it has been found to be more advantageous to shift the apparatus of the present invention horizontally, in relation to the tire, in order to selectively allow only one rotating drum at a time to be used to contact the tire. Removing the second drum from contacting the tire has been found to enable the tire to be more easily displaced over the flange of the rim. A secondary benefit from having a displaced drum is the use of its elevating motion to elevate rotating dowels, described below. Once the tire and wheel assembly is suspended above the ground, an assembly of two rotating dowels included in the apparatus of the present invention are moved into position to accomplish their task. The wide variation in sizes of rims and tires used on various vehicles requires a wide range of settings for the rotating dowels to be properly positioned. The offset (displaced) drum and its elevating ability acts as the mechanism for this positioning. A third benefit from this design is that the two separate drums can be powered by two different motors having different speeds. A lower speed, higher torque, motorized drum is used in the mounting, dismounting and cutting of tires. While a second, higher speed lower torque motor may be used for rotating the offset drum so as to rotate the tire and wheel assembly for the purpose of balancing tires and wheels on a vehicle. The two motorized drums, with their two different speeds, do not interfere with each other, since they do not touch the tire at the same time during rotation.
In order to shift the apparatus of the present invention from one drum in contact with the tire to the other drum in contact with the tire, the present invention includes a unique jack stand that allows for lateral movement of the apparatus, while also providing stability during operation of the apparatus. Due to the employment of an elevation mechanism within the apparatus, no separate elevating jack, as described in the ""516 patent is needed. This lowers the weight and allows increased mobility of the apparatus of the present invention. It also makes the apparatus an all-in-one machine and, therefore, easier to operate.
The ""516 patent utilized xe2x80x9chatsxe2x80x9d for breaking the beads of a tire from the flange of a rim. However, the present invention uses a dowel carriage having a linear dowel shaft, upon which two dowels linearly move. One dowel is locked in position while the other dowel is moved laterally across the face of a wheel to break the seal between the bead of the tire and the flange of the rim. The process is then repeated with the dowels reversed to break the seal of the opposite bead. The dowel continues it""s movement laterally across the width of the wheel thereby displacing both of the tire beads over the flange of the rim. The method of the present invention allows the wheel to rotate during the mounting and dismounting process, thereby providing the benefits of increased speed and convenience as described herein.
Therefore, there exists a need in the art for an apparatus that more efficiently mounts and dismounts tires onto wheels without the need for taking the wheels off the vehicle. And, further still there exists a need in the art for a machine that more efficiently cuts old tires before they are removed from a wheel, to change their shape and volume to make them easy to handle and less costly to dispose of
Accordingly, it is a general object of the present invention to provide an improved tire changer apparatus. It is a particular object of the present invention to provide an improved tire changer apparatus and method for using the same. It is another particular object of the present invention to provide an improved tire changing apparatus, which may also cut tires off of a wheel, while the wheel is still attached to the vehicle, in order to provide easier disposal of the old tire. It is yet another particular object of the present invention to provide an improved tire changing apparatus having means for elevating a vehicle""s rim and tire assembly off the ground. It is yet a further particular object of the present invention to provide an improved tire changing apparatus and method, which includes a jack stand to support a vehicle and a pair of drums that, upon being fastened around a tire, collapse together and raise upwardly to aid in mounting, dismounting and cutting tires from wheels, while the wheels are still attached to a vehicle. It is yet a still further particular object of the present invention to provide an improved tire changing apparatus and method of use, includes a means for deflecting beads of a tire over a flange on a wheel that remains on a vehicle, by means of a rotating dowel affixed to the apparatus while the tire and wheel rotate on the vehicle. And, it is a particular object of the present invention to provide an apparatus having a plurality of separate carriages, secured together to work as a single apparatus.
These and other objects of the present invention are achieved by providing a tire changing device having three independent carriages for placement under a vehicle and around a wheel and tire assembly which is still attached to the vehicle. The device is used to raise the vehicle and break the seals between the tire beads and flanges of the wheel. The device may also cut the old tire being removed from the wheel into more than one part for easy disposal. The tire changing device of the present invention is formed with a pair of drums on two separate carriages used to selectively rotate a tire and wheel assembly for various reasons. A first carriage includes a bead deflection device, while a second carriage includes a drum for rotating a deflated tire to enable the tire changing device of the present invention to install a tire on or remove a tire from the wheel.
The novel method of the present invention includes the steps of positioning the device under a tire and wheel assembly; raising the wheel and tire assembly off the ground by use of the device; deflating the tire and lowering the vehicle onto a jack stand; moving a first drum into contact with the deflated tire and wheel assembly; moving a dowel assembly having knives therein into contact with the crown of the tire; turning the tire by rotating the first drum to cut the tire; removing the cut thread portion of the tire; contacting the sidewalls of the tires with dowels in a manner to break the tires"" seal to the flange of the wheel and remove the remaining portion of the sidewall from the wheel. In some instances, the tire will not be cut, and the knife setting and cutting steps will be eliminated.
The novel method of the present invention is also used to mount a new tire onto an empty wheel, which is still fastened to the vehicle. The vehicle and wheel are usually in a position to provide sufficient clearance; to allow the tire to be mounted; the dowel tire bead deflectors, if not already in position, are moved to the tire to be mounted; the new tire is then turned and the dowels deflect the tire beads over the flange of the wheel to secure the tire loosely onto the wheel; the tire is then inflated to seal the tire beads to the flanges of the wheel. The tire and wheel may then be rotated by a further drum brought into contact with the inflated tire, so as to allow the tire and wheel to be balanced.